The Phoenix plate. Relief from Copernicus GLO-30; rivers and lakes from USGS NHD; watersheds from the USGS Watershed Boundary Dataset; roads and city limits from Census TIGER 2024.
93° on Nov. 12, 1999, the hottest reading for this week of the year since 1895. Next is 92° in 1967.
Phoenix’s center stands about 1,100 ft above sea level. Within three miles the land runs from 1,040 ft to 1,130 ft, a difference of 90 ft: gently rolling country. The highest named summit within 15 miles is Mount Suappoa, about 2,670 ft, 8 miles south.
Under the town center the state geologic map shows Holocene surficial deposits (silt, clay), from the Holocene, less than 10,000 years old.
The section below crosses 5 rock units mapped at the surface.
Heights every 0.1 mile from the Copernicus GLO-90 surface model; vertical exaggeration about 16×. The colored band under the surface is the rock the state geologic map shows at the surface, not a picture of what lies beneath.
Silt, clay. Age: Holocene, less than 10,000 years old. About 11 mi of the line.
Gravel, sand. Age: Pleistocene, less than 0.8 million years old. About 7 mi of the line.
Sand, gravel. Age: Holocene, less than 10,000 years old. About 3 mi of the line.
Granite, granodiorite, diorite. Age: Late Oligocene to Middle Miocene, 14 to 26 million years old. About 3 mi of the line.
Metasedimentary, metavolcanic, gneiss. Age: Paleoproterozoic, 1.6 to 1.8 billion years old. About 0.7 mi of the line.
From the USGS State Geologic Map Compilation (Horton and others, 2017), the states’ geologic maps joined at a common scale.
Heights from Copernicus GLO-90 (a surface model: it includes buildings and tree canopy); summits from USGS GNIS; rivers from USGS NHDPlus HR; rock from the USGS State Geologic Map Compilation.
A raindrop that lands in Phoenix reaches the Gulf of California by way of Skunk Creek, the New River, the Agua Fria, the Gila and the Colorado: about 360 river miles.
200 miles of the trip are on the Gila.
Often dry. About 70% of the way is mapped as streams that run only after rain or snowmelt; the water makes the whole trip in floods.
Seldom reaches the sea. Dams and canals now take nearly all of the Colorado before its old delta in Mexico.
Traced down the USGS NHDPlus V2.1 river network from the Census center point of Phoenix; river miles along the main stem, rounded.
Phoenix has a hot desert climate. Summer afternoons average 107° in July; winter nights fall to about 45° in December. About 7 inches of rain fall in a normal year.
On November 14 Phoenix normally reaches 77° and falls to 54°. The record high is 91°, in 1999; the record low 28°, in 1916. The most rain on this date, 1.58 in, fell in 1993.
Normals 1991–2020 and records since 1895 from the Phoenix Area threaded record (Phoenix Airport, 4 miles east-southeast). NOAA, through RCC-ACIS.